Composite ammonium diuranate gel particles with a phenolic resin phase, and methods of making the same

Abstract

Composite gel particles with an ammonium diuranate matrix phase and a phenolic resin phase incorporated within the ammonium diuranate matrix phase are produced from a first solution comprising uranyl nitrate, a phenol, and optionally formaldehyde, wherein the uranyl nitrate and the phenol are present in a ratio ranging from 2:1 to 25:1; and a second solution comprising hexamethylenetetramine and urea. The first solution and the second solution are mixed, and drops of the resulting mixture into a heated second liquid which is immiscible with the mixed solution. Heat from the second liquid causes the hexamethylenetetramine to decompose to form ammonia, which reacts with the uranyl nitrate to cause each of the drops to form an ammonium diuranate gel particle. The ammonium diuranate gel particles are collected. The ammonium diuranate gel particles include the phenolic resin phase within the ammonium diuranate matrix phase, where the phenolic resin phase is formed by reaction between the phenol and formaldehyde. The first solution may include uranyl nitrate, the phenol, and formaldehyde, and the formaldehyde and the phenol may react to form the phenolic resin phase prior to mixing the first solution and the second solution. The first solution may be free of formaldehyde, and heat from the second liquid may causes the hexamethylenetetramine to decompose to form formaldehyde in situ; so that the formaldehyde and the phenol react to form the phenolic resin phase while the ammonia reacts with the uranyl nitrate.